This invention relates to flexible couplings for connecting and transmitting torque between two shafts or other rotatable parts and especially to a coupling that can accommodate a certain amount of angular or parallel misalignment, or both, between the shafts. More particularly, the invention relates to a flexible coupling capable of connecting rotary shafts with their respective axes angularly and/or laterally misaligned while maintaining a generally constant velocity relationship.
Flexible couplings for use between shafts that have their axes misaligned either through error or by design are available in the art for many applications; however, these are limited in capability, both as to their durability and the permissable range of angular or parallel misalignment between their axes. Some of these utilize elastomeric material to accommodate misalignment but they are vulnerable to failure due to heat generation. They also lack torsional stiffness and can accommodate only slight angles of axial misalignment such as one or two degrees.
On the other hand conventional flexible couplings which use flexing elements which are non-elastomeric are subject to extremely high stresses and are thus limited to very small amounts of misalignment such as one-half a degree or one degree.
Other non-elastomeric types of flexible couplings such as universal joints and especially universal joints of the Cardan type permit a high degree of shaft misalignment such as at angles of 10 degrees or more; however, they do not provide a constant velocity relationship between the rotating shafts. Some special types of universal joints do provide a constant velocity relationship, however, these are subject to large amounts of bearing wear and must be provided with lubricated bearings and seals.
The flexible coupling of the present invention reduces the difficulties indicated above and affords other features and advantages heretofore not obtainable.